using System;

using System.Threading.Tasks;

using System.Collections.Concurrent;    

public class Program

{

    public static void Main()

    {

        PopulateQueueParallel(new ConcurrentQueue<string>(), 5000);

    }

    static void PopulateQueueParallel(ConcurrentQueue<string> queue, int queueSize)

    {

        Parallel.For(0, queueSize, (i) => queue.Enqueue(string.Format("my message {0}", i)));

        Parallel.For(0, queueSize,

            (i) =>

            {

                string message;

                bool success = queue.TryDequeue(out message);

                if (!success)

                    throw new Exception("Error!");

                Console.WriteLine(message);

            });

    }

}